The report, released today, details how 30 national landmarks across the United States may be irreparably damaged or even lost forever due to the effects of climate change. The threatened sites span the continent from Florida to Alaska and encompass eras from prehistory to the space age. "It's the whole sweep of American history," says Adam Markham, director of climate impacts for the UCS.

Amid all the concern over climate change, relatively little attention has been paid to how it will affect cultural resources. "It's an ignored issue in the world of climate change assessment," says Markham. "We needed to fill that gap because the threats are quite alarming."

The report, called "National Landmarks at Risk," does not encompass all historic sites affected by climate change. "We looked for places," says Markham, "where there was a very strong set of climate data which enabled us to see impacts happening now or in the future that are attributable or consistent with climate change."

Along the Atlantic coast north of Cape Hatteras, North Carolina, sea levels have risen four times the national average, and historic downtowns face inundation. Boston's Faneuil Hall, where the Sons of Liberty plotted the Boston Tea Party, lies within the city's hundred-year tidal flood zone, which has experienced as many extreme high tides in the past decade as it had in the previous 80 years. (Read "Rising Seas" in National Geographic magazine.)

In Annapolis, Maryland, home of the U.S. Naval Academy and the first post-Revolutionary War capitol, storm surges have caused water to "ascend three feet or more above mean sea level at least 10 times" in the past decade, according to the report.

Jamestown, the site of the first permanent English colony in North America, could actually disappear. The settlement is located on an island that sits less than five feet above sea level. Virginia's coastal waters are projected to rise up to six feet by 2100.

One of the country's newest national monuments may not survive the century. Harriet Tubman Underground Railroad National Monument, signed into existence by President Obama in 2013, may be largely submerged by 2050. Located along the Chesapeake Bay, the park reflects the wetland landscape that Tubman traveled through as she guided local slaves to freedom.

"It's very vulnerable," says Mary Foley, regional chief scientist with the National Park Service. "We're going to see higher flood events, higher tides, and loss of marshes to open water."

Even sites from recent history will require drastic changes to last into the next generation. NASA, a major provider of global data on climate change, is dealing with rising seas at many of its locations. According to the report, "More than two-thirds of NASA facilities [are] within 16 feet of sea level," including the Kennedy Space Center launch pads from which the Apollo missions and the space shuttles lifted into space. NASA has restored nearby protective dunes several times, but storm surges still break through.

At NASA's oldest site, Langley Research Center in Hampton, Virginia, aging buildings are being torn down and rebuilt as far from the Chesapeake Bay as property lines allow. But right now, says Russell De Young, a senior research scientist at Langley, "storm surges from nor'easters and hurricanes could inundate the whole facility and make it unusable."

Too Little Water

Across the western U.S., the danger comes from too little water. Fires in the archaeologically rich Southwest are now longer, hotter, and larger as rising temperatures increase the likelihood of drought and lengthen the fire season.

Flames damage artifacts that have endured for millennia—for instance, burning off the ceramic glazes that allow archaeologists to date pottery.

"Fire resets the clock. It removes artifacts from time," says Rachel Loehman, a U.S. Forest Service ecologist who studies the effects of fire and climate change on artifacts. "If we start losing the archaeological record, we're never going to get it back."